Endoscopic imaging system

ABSTRACT

An endoscopic imaging system includes a reusable control cabinet having a number of actuators that control the orientation of a lightweight endoscope that is connectable thereto. The endoscope is used with a single patient and is then disposed. The endoscope includes an illumination mechanism, an image sensor and an elongate shaft having one or more lumens located therein. A polymeric articulation joint at the distal end of the endoscope allows the distal end to be oriented by the control cabinet. The endoscope is coated with a hydrophilic coating that reduces its coefficient of friction and because it is lightweight, requires less force to advance it to a desired location within a patient.

FIELD OF THE INVENTION

[0001] The present invention relates to medical devices in general andtherapeutic and diagnostic endoscopes in particular.

BACKGROUND OF THE INVENTION

[0002] As an aid to the early detection of disease, it has become wellestablished that there are major public health benefits from regularendoscopic examinations of internal structures such as the esophagus,lungs, colon, uterus, and other organ systems. A conventional imagingendoscope used for such procedures comprises a flexible tube with afiber optic light guide that directs illuminating light from an externallight source through a lens at the distal end of the endoscope whichfocuses the illumination on the tissue to be examined. An objective lensand fiber optic imaging light guide communicating with a camera at theproximal end of the scope, or an imaging camera chip at the distal tip,transmit an image to the examiner. In addition, most endoscopes includeone or more working channels through which medical devices such asbiopsy forceps, snares, fulguration probes, and other tools may bepassed.

[0003] Navigation of the endoscope through complex and tortuous paths iscritical to success of the examination with minimum pain, side effects,risk or sedation to the patient. To this end, modern endoscopes includemeans for deflecting the distal tip of the scope to follow the pathwayof the structure under examination, with minimum deflection or frictionforce upon the surrounding tissue. Control cables similar to puppetstrings are carried within the endoscope body and connect a flexibleportion of the distal end to a set of control knobs at the proximalendoscope handle. By manipulating the control knobs, the examiner isusually able to steer the endoscope during insertion and direct it tothe region of interest, in spite of the limitations of such traditionalcontrol systems, which are clumsy, non-intuitive, and friction-limited.Common operator complaints about traditional endoscopes include theirlimited flexibility, limited column strength, and limited operatorcontrol of stiffness along the scope length.

[0004] Conventional endoscopes are expensive medical devices costing inthe range of $25,000 for an endoscope, and much more for the associatedoperator console. Because of the expense, these endoscopes are built towithstand repeated disinfections and use upon many patients.Conventional endoscopes are generally built of sturdy materials, whichdecreases the flexibility of the scope and thus can decrease patientcomfort. Furthermore, conventional endoscopes are complex and fragileinstruments which can frequently need expensive repair as a result ofdamage during use or during a disinfection procedure. To overcome theseand other problems, there is a need for a low cost imaging endoscopethat can be used for a single procedure and thrown away. The scopeshould have better navigation and tracking, a superior interface withthe operator, improved access by reduced frictional forces upon thelumenal tissue, increased patient comfort, and greater clinicalproductivity and patient throughput than those that are currentlyavailable.

SUMMARY OF THE INVENTION

[0005] To address these and other problems in the prior art, the presentinvention is an endoscopic video imaging system. The system includes amotion control cabinet that includes a number of actuators that controlthe orientation of an endoscope and an imaging system to produce imagesof tissue collected by an image sensor at the distal end of theendoscope. A single use endoscope is connectable with the controlcabinet and used to examine a patient. After the examination procedure,the endoscope is disconnected and disposed of.

[0006] The endoscope of the present invention includes a flexibleelongate tube or shaft and an illumination source that directs lightonto a tissue sample. An image sensor and objective lens at or adjacentthe distal end of the endoscope captures reflected light to produce animage of the illuminated tissue. Images produced by the sensor aretransmitted to a display device to be viewed by an examiner. In oneembodiment, the illumination source comprises one or more light emittingdiodes (LEDs) and the image sensor comprises a CMOS solid state imagesensor.

[0007] The endoscope of the present invention also includes a steeringmechanism such as a number of tensile control cables, which allow thedistal end of the endoscope to be deflected in a desired direction. Inone embodiment of the invention, a proximal end of the tensile controlcables communicates with actuators within the control cabinet. Afreestanding joystick controller generates electrical control signalswhich the control cabinet uses to compute signals to drive the actuatorsthat orient the distal end of the endoscope in the direction desired bythe examiner. In another embodiment of the invention, the distal end ofthe endoscope is automatically steered, or provided to the examiner,based on analysis of images from the image sensor.

[0008] In one embodiment of the invention, the endoscope includes apolymeric articulation joint adjacent its distal end that aids inbending the distal end of the scope in a desired direction. Thearticulation joint is constructed as a number of live hinges integratedinto a unified structure of the required overall properties anddimensions. Tension of the control cables causes the live hinges of thearticulation joint to deflect, thereby bending the distal tip of theendoscope. In one embodiment of the invention, the articulation jointexerts a restoring force such that upon release of a tensioning force,the distal end of the scope will straighten.

[0009] In an alternative embodiment, the articulation joint comprises anumber of stacked discs that rotate with respect to one another. Controlcables pass through the discs and pull adjacent discs together to turnthe distal end of the endoscope.

[0010] In another embodiment of the invention, the endoscope has avariation in stiffness along its length that allows the distal end to berelatively flexible while the more proximal regions of the scope haveincreased column strength and torque fidelity so that a physician cantwist and advance the endoscope with greater ease and accuracy and withfewer false advances (“loops”). Variation in stiffness along the lengthcan be provided by varying the durometer of materials that comprise ashaft of the endoscope. Operator-controlled, variable stiffness can beprovided by control cables that can be tightened or loosened to adjustthe stiffness of the shaft. In yet another embodiment, the spacingbetween the live hinges of the articulation joint is selected to providea variation in stiffness along the length of the articulation joint.

[0011] In yet another embodiment of the invention, the endoscope iscovered with a retractable sleeve that uncovers the distal end of thescope during use and extends over the distal end after the scope isremoved from a patient.

[0012] In another embodiment of the invention, the scope is coated witha hydrophilic coating to reduce its coefficient of friction.

[0013] In another embodiment of the invention, the scope is retractablein a longitudinal direction. The distal end of the scope is extendableusing a spring, pull wires, bellows or the like to allow a physician tomove the distal tip without having to alter the position of the shaft ofthe endoscope.

[0014] In yet another embodiment of the invention, the endoscopeincludes a heat dissipating mechanism for removing heat produced by theillumination source and image sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The foregoing aspects and many of the attendant advantages ofthis invention will become more readily appreciated as the same becomebetter understood by reference to the following detailed description,when taken in conjunction with the accompanying drawings, wherein:

[0016]FIGS. 1A and 1B illustrate two possible embodiments of anendoscopic video imaging system in accordance with the presentinvention;

[0017]FIG. 2 illustrates further detail of an endoscope used in theimaging system shown in FIG. 1A;

[0018]FIG. 3A is a block diagram of a motion control cabinet thatinterfaces with an imaging endoscope in accordance with one embodimentof the present invention;

[0019]FIG. 3B is a block diagram of a motion control cabinet thatinterfaces with an imaging endoscope in accordance with anotherembodiment of the present invention;

[0020]FIGS. 4A-4D illustrate one mechanism for connecting the visionendoscope to a motion control cabinet;

[0021]FIG. 5 is a detailed view of one embodiment of a handheldcontroller for controlling an imaging endoscope;

[0022]FIG. 6 illustrates one embodiment of a distal tip of an imagingendoscope in accordance with the present invention;

[0023]FIG. 7 illustrates one mechanism for terminating a number ofcontrol cables in a distal tip of an imaging endoscope;

[0024]FIG. 8 illustrates an imaging endoscope having control cablesrouted through lumens in the walls of an endoscope shaft;

[0025]FIGS. 9A and 9B illustrate a transition guide that routes controlcables from a central lumen of an endoscope shaft to lumens in anarticulation joint;

[0026]FIGS. 10A and 10B illustrate the construction of a shaft portionof an endoscope in accordance with one embodiment of the presentinvention;

[0027]FIG. 1I illustrates one mechanism for providing a shaft having avarying stiffness along its length;

[0028]FIGS. 12A and 12B illustrate an extrusion used to make anarticulation joint in accordance with one embodiment of the presentinvention;

[0029]FIG. 13 illustrates an articulation joint in accordance with oneembodiment of the present invention;

[0030]FIGS. 14 and 15 illustrate an extrusion having areas of adifferent durometer that is used to form an articulation joint inaccordance with another embodiment of the present invention;

[0031]FIGS. 16A and 16B illustrate another embodiment of an articulationjoint including a number of ball and socket sections;

[0032]FIGS. 17A-17D illustrate various possible configurations of balland socket sections used to construct an articulation joint;

[0033]FIGS. 18A-18B illustrate an articulation joint formed of a numberof stacked discs in accordance with another embodiment of the presentinvention;

[0034]FIGS. 19A-19B illustrate a disc used to form an articulation jointin accordance with another embodiment of the present invention;

[0035]FIGS. 20A-20B illustrate a disc used to form an articulation jointin accordance with another embodiment of the present invention;

[0036]FIGS. 21A-21B illustrate a non-circular segment used to form anarticulation joint in accordance with another embodiment of the presentinvention;

[0037]FIG. 22 illustrates an endoscope having a braided member as anarticulation joint in accordance with another embodiment of the presentinvention;

[0038]FIG. 23 illustrates one possible technique for securing the endsof a control wire to a braided articulation joint;

[0039]FIG. 24 illustrates a shaft having one or more memory reducingwraps in accordance with another embodiment of the present invention;

[0040]FIG. 25 illustrates a shaft including longitudinal stripes of ahigh durometer material in accordance with another embodiment of thepresent invention;

[0041]FIGS. 26-29 illustrate alternative embodiments of a grippingmechanism that rotates an imaging endoscope shaft in accordance with thepresent invention;

[0042]FIGS. 30A and 30B illustrate a retractable sleeve used withanother embodiment of the present invention;

[0043]FIG. 31 illustrates one embodiment of a heat dissipating distaltip of an endoscope in accordance with the present invention; and

[0044]FIGS. 32 and 33 illustrate alternative embodiments of a heatdissipating distal tip in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0045] As indicated above, the present invention is an endoscopic videoimaging system that allows a physician to view internal body cavities ofa patient as well as to insert surgical instruments into the patient'sbody. An imaging endoscope used with the present invention issufficiently inexpensive to manufacture such that the endoscope can beconsidered a disposable item.

[0046] As shown in FIG. 1A, an endoscopic video imaging system 10according to one embodiment of the present invention includes an imagingendoscope 20, a motion control cabinet 50 and a handheld controller 80.The imaging endoscope 20 has a distal tip 22 that is advanced into apatient's body cavity and a proximal end 24 that is connected to themotion control cabinet 50. As will be explained in further detail below,the motion control cabinet 50 includes a number of actuators thatcontrol a steering mechanism within the endoscope in order to change theorientation of the distal tip 22. A physician or their assistant usesthe handheld controller 80 to input control signals that move the distaltip 22 of the imaging endoscope 20. In addition, the motion controlcabinet 50 may include connections to sources of air/gas and a flushingliquid such as water for clearing the imaging endoscope. The motioncontrol cabinet 50 also includes imaging electronics to create and/ortransfer images received from an image sensor to a video display forviewing by a physician or technician.

[0047] In the embodiment shown, the imaging endoscope 20 also includes abreakout box 26 that is positioned approximately midway along the lengthof the endoscope. The breakout box 26 provides an attachment point for avacuum bottle 40 that collects liquids from a lumen within the imagingendoscope. The vacuum bottle 40 is controlled by a vacuum valve 28 thatis positioned on the breakout box 26. Alternatively, the valve can bepositioned within the motion control cabinet 50 and controlled from thehandheld controller 80.

[0048] If desired, the handheld controller 80 can be secured to thebreakout box 26 such that the two units can be moved as one if desired.Upon completion of a patient examination procedure, the imagingendoscope 20 is disconnected from the motion control cabinet 50 anddisposed of. A new imaging endoscope 20 is then connected to the motioncontrol cabinet 50 for the next examination procedure to be performed.

[0049] The embodiment shown in FIG. 1A is a “parallel” configurationwhereby the endoscope 20 and handheld controller 80 are separatelyplugged into different connectors of the motion control cabinet 50. Thisparallel configuration allows one operator to handle the endoscope whileanother operator can handle the handheld controller 80. Alternatively,the handheld controller 80 may be secured to the endoscope 20 such thata single operator can control both. FIG. 1B illustrates a “serial”configuration of the invention. Here, the imaging endoscope 20 isconnected to the motion control cabinet 50 through the handheldcontroller 80.

[0050]FIG. 2 shows further detail of one embodiment of the imagingendoscope 20. At the proximal end of the endoscope is a low torque shaft24 and a connector 34 that connects the endoscope 20 to the motioncontrol cabinet 50. Distal to the breakout box 26 is a higher torqueshaft. At the distal end of the endoscope 20 is the distal tip 22 thatincludes a light illumination port, an image sensor, an entrance to aworking lumen and a flushing lumen (not shown). Proximal to the distaltip 22 is an articulation joint 30 that provides sufficient flexibilityto the distal section of the shaft such that the distal tip 22 can bedirected over an angle of 180 degrees by the steering mechanism.

[0051] As discussed above, the endoscope 20 in accordance with oneembodiment of the invention, has a higher torque shaft at the distalsection of the endoscope and a lower torque shaft at its proximal end.The breakout box 26 positioned along the length of the endoscope shaftcan be used as a handle or gripper to impart rotation of the distal endof the endoscope during a medical examination procedure. The highertorque portion of the shaft transfers rotational motion that is impartedat a location proximal to the distal tip in order to guide the distaltip of the imaging catheter. The low torque shaft portion of the imagingcatheter does not transfer torque as well and can twist when rotationalmotion is applied.

[0052] In use, the physician can insert a medical device such as abiopsy forceps, snare, etc., into a connector 32 found on the breakoutbox 26 that leads to a working channel lumen in the endoscope. Inalternate embodiments, the entrance to the working channel lumen may bepositioned further towards the proximal end of the endoscope.

[0053]FIG. 3A is a block diagram of the major components included withinone embodiment of the motion control cabinet 50. The motion controlcabinet is preferably positioned on a cart that is wheeled near apatient prior to an examination procedure. The motion control cabinet isconnected to a source of electrical power, either A.C. mains or abattery, as well as to a source of insufflation gas and irrigationliquid. Inside the motion control cabinet 50 is a controller interface52 that is connected to the handheld controller 80 and receives controlsignals therefrom. To change the orientation of the distal tip of theimaging endoscope, the control signals are received from a directionalswitch in the handheld controller 80. The control signals are suppliedto a servo motor controller 54 that in turn controls a number ofactuators, such as servo motors 56 a, 56 b, 56 c, 56 d. Each of theservo motors 56 a-56 d is connected to one or more control cables withinthe imaging endoscope. Motion of the servo motors 56 a-56 d pulls orreleases the control cables in order to change the orientation of thedistal tip 22 of the imaging endoscope 20. Although the embodiment shownin FIG. 3A shows four servo motors and control cables, it will beappreciated that fewer or more servo motors and corresponding controlcables could be used to move the distal tip. For example, some imagingendoscopes may use three control cables and three associated servomotors.

[0054] Also included in the motion control cabinet 50 is a power source58 that provides electrical power to a light source such as a number oflight emitting diodes (LEDs) at the distal end 22 of the imagingendoscope. Alternatively, if the imaging catheter utilizes an externallight source, then the motion control cabinet can include a highintensity light source such as a laser or Xenon white light source thatsupplies light to a fiber optic illumination guide within the imagingendoscope 20 in order to illuminate an internal body organ. The powersource 58 may be controlled by control signals received from thehandheld controller 80 when the user desires to activate the lightsource.

[0055] An imaging electronics board 60 captures images received from animage sensor (not shown) at the distal end of the imaging endoscope. Theimaging electronics board 60 can enhance the images received or canprovide video effects such as zoom, color changes, highlighting, etc.,prior to display of the images on a video display (not shown). Images ofthe tissue may also be analyzed by the imaging electronics board 60 toproduce control signals that are supplied to the servo motor controller54 in order to automatically steer the distal tip of the endoscope aswill be discussed in further detail below. Images produced by theimaging electronics board 60 may also be printed on a digital printer,saved to a computer readable media such as a floppy disk, CD, DVD, etc.,or a video tape for later retrieval and analysis by a physician.

[0056] Finally, the motion control cabinet 50 includes valves 70 thatcontrol the delivery of insufflation air/gas to insufflate a patient'sbody cavity and an irrigation liquid to flush out a body cavity and/orclean the imaging light source and image sensor at the distal end of theendoscope. The insufflation air/gas and irrigation liquid are connectedto the imaging catheter via a connector 38 that connects to anirrigation/insufflation lumen of the imaging endoscope 20. In oneembodiment of the invention, the irrigation and insufflation lumen arethe same lumen in the imaging catheter. However, it will be appreciatedthat separate irrigation and insufflation lumens could be provided ifdesired and if space in the endoscope permits.

[0057]FIG. 3B illustrates another embodiment of a motion control cabinet50A that is similar to the cabinet shown in FIG. 3A. The motion controlcabinet 50A includes a vacuum valve 71 that controls vacuum delivered toa vacuum collection bottle 40. A vacuum line 73 connects to a vacuumlumen within the imaging endoscope 20. The vacuum valve 71 is controlledfrom the handheld controller 80.

[0058]FIGS. 4A-4D illustrate one mechanism for securing the proximal endof the imaging endoscope to the control cabinet 50 prior to performingan endoscopic examination. The control cabinet 50 includes a connector34A having a number of shafts 57 that are driven by the servo motors 56shown in FIGS. 3A and 3B. Each shaft 57 is shaped to be received in acorresponding spool on which the control cables are wound. Also includedin the connector 34A are connections to the insufflation and irrigationvalves 70 and vacuum valve 71 to provide air, water and vacuum to theendoscope.

[0059]FIGS. 4A and 4B illustrate one possible connector 34 found at theproximal end of the endoscope 20 for securing the endoscope to themotion control cabinet 50. The connector 34 includes a number ofthumbscrews 77 or other quick release mechanisms that allow theconnector 34 to be easily secured to the connector 34A on the motioncontrol cabinet. As shown in FIG. 4C, the connector 34A includes anumber of spools 79 about which the control cables are wound. Each spoolis preferably threaded or grooved to prevent the control cables frombinding on the spool during use. A cover may surround a portion of thespool to keep the control cables against the spool and to aid insupporting the spool within the connector 34. In one embodiment of theinvention, the spools are prevented from rotating when the connector isnot engaged with the motion control cabinet 50 by brakes 81 having pinsthat fit within corresponding slots in the spool. Once the connector 34is mounted to the motion control cabinet 50, the brakes 81 aredisengaged from the spool such that the spool can be moved by the servomotors. Electrical connections for the light source and image sensor aswell as connections to the air and water valves can be found on thesides of the connector or on the rear face of the connector 34 to engagethe valves, as shown in FIG. 4A.

[0060]FIG. 4D illustrates a cross-sectional view of a shaft 57 fittedwithin a spool 79. The shaft 57 is supported by a cylinder 59 having aspring 61 therein such that the shaft 57 is free to move within thecylinder 59. The cylinder 59 is directly coupled to the servo motorswithin the motion control cabinet. The spring 61 allows the shaft 57 tofloat such that the shaft can more easily align and engage the matingsurface of the spool 79.

[0061] Upon insertion of the shaft 57 into the spool 79, the brake 81 isreleased, thereby allowing the spool 79 to be moved by rotation of thecylinder 59. In some instances, the brake 81 may be omitted, therebyallowing the spools 79 to freely rotate when the connector 34 is notengaged with the motion control cabinet 50.

[0062]FIG. 5 illustrates various controls located on the handheldcontroller 80 in accordance with one embodiment of the invention. Thehandheld controller 80 includes a controller body 82 that, in theparallel embodiment of the invention, is coupled to the motion controlcabinet 50 by an electrical cord 84, a wireless radio frequency channel,an infrared or other optical link. If the connection is made with anelectrical cord, a strain relief 86 is positioned at the junction of theelectrical cord 84 and the body 82 of the controller to limit thebending of the electrical wires within the electrical cord 84. In theserial embodiment of the invention, the connection of the handheldcontroller 80 to the motion control cabinet 50 is made with a conductorthat includes both the wires to transmit signals to the motioncontrollers and imaging systems, as well as a lumens to carry theinsufflation air/gas and irrigation liquid. In addition, the controlcables of the endoscope engage cables connected to the actuators in themotion control cabinet through the handheld controller 80.

[0063] Positioned in an ergonomic arrangement on the handheld controller80 are a number of electrical switches. An articulation joystick 88 orother multi-positional device can be moved in a number of positions toallow the physician to orient the distal tip of the imaging endoscope ina desired direction. In order to guide the imaging endoscope manually,the physician moves the joystick 88 while watching an image on a videomonitor or by viewing the position of the distal tip with another medialimaging technique such as fluoroscopy. As the distal tip of theendoscope is steered by moving the joystick 88 in the desired direction,the physician can push, pull and/or twist the endoscope to guide thedistal tip in the desired direction.

[0064] A camera button 90 is provided to capture an image of an internalbody cavity or organ in which the imaging endoscope 20 is placed. Theimages collected may be still images or video images. The images may beadjusted for contrast or otherwise enhanced prior to display or storageon a recordable media.

[0065] An irrigation button 92 activates an irrigation source to supplya liquid such as water through an irrigation lumen of the imagingendoscope. The liquid serves to clean an image sensor and the lightsource at the distal end of the endoscope as well as an area of the bodycavity. An insufflation button 94 is provided to activate theinsufflation source within the motion control cabinet 50 to supplyair/gas through a lumen of the catheter. The supply of the insufflationgas expands portions of the body cavity around the distal tip of theendoscope so that the physician can more easily advance the endoscope orbetter see the tissue in front of the endoscope.

[0066] In one embodiment of the invention, the handle 82 also includes athumb screw 96 for securing the handheld controller 80 to the breakoutbox 26 as indicated above. A corresponding set of threads on a breakoutbox 26 receive the thumb screw 96 in order to join the two partstogether. One or more additional buttons 98 may also be provided toactivate additional functions such as recording or printing images,adjusting light intensity, activating a vacuum control valve, etc., ifdesired.

[0067] The endoscope of the present invention may also be steeredautomatically. Images received by the imaging electronics 60 areanalyzed by a programmed processor to determine a desired direction ororientation of the distal tip of the endoscope. In the case of acolonoscopy, where the endoscope is advanced to the cecum, the processorcontrols the delivery of insufflation air/gas to inflate the colon, theprocessor then analyzes the image of the colon for a dark spot thatgenerally marks the direction in which the scope is to be advanced. Theprocessor then supplies control instructions to the servo controller 54such that the distal tip is oriented in the direction of the dark spotlocated.

[0068] In other modes, a processor in the motion control cabinet causesthe distal tip of the endoscope to move in a predefined pattern. Forexample, as the scope is being withdrawn, the distal tip may be causedto move in a search pattern such that all areas of a body cavity arescanned for the presence of disease. By using the automatic control ofthe distal tip, a physician only has to advance or retract the scope toperform an examination.

[0069] As will be described in further detail below, the imagingendoscope 20 generally comprises a hollow shaft having one or morelumens formed of polyethylene tubes which terminate at the distal tip22. As shown in FIG. 6, one embodiment of a distal tip 110 comprises acylinder having a distal section 112 and a proximal section 114. Theproximal section 114 has a smaller diameter than the diameter of thedistal section 112 in order to form a stepped shoulder region. Thediameter of the shoulder is selected that shaft walls of the endoscopecan seat on the shoulder region to form a smooth outer surface with thedistal section 112. The distal face of the distal tip 110 includes anumber of ports, including a camera port 116, one or more illuminationports 118, an access port or working channel lumen 120, and adirectional flush port 122.

[0070] Fitted within the camera port 116 is an image sensor (not shown)that preferably comprises a CMOS imaging sensor or other solid statedevice and one or more glass or polymeric lenses that produce electronicsignals representative of an image of the tissue in front of the cameraport 116. The image sensor is preferably a low light sensitive, lownoise video VGA, CMOS, color imager or higher resolution sensor such asSVGA, SXGA, or XGA. The video output of the sensor may be in anyconventional format including PAL, NTSC or high definition video format.

[0071] The illumination port 118 houses one or more lenses and one ormore light emitting diodes (LEDs) (not shown). The LEDs may be highintensity white light sources or may comprise colored light sources suchas red, green and blue LEDs. With colored LEDs, images in differentspectral bands may be obtained due to illumination with any-one or moreindividual colors. White light images may be obtained by thesimultaneous or sequential illumination of the colored LEDs andcombining individual color images. As an alternative to LEDs, the lightsource may be external to the endoscope and the illumination lightdelivered to the illumination port with a fiber optic bundle.

[0072] The access port 120 is the termination point of the workingchannel or lumen of the endoscope 20. In the embodiment described above,the proximal end of the working channel terminates at the breakout box26 as shown in FIG. 2. However, the working channel could terminatenearer the proximal end of the imaging catheter.

[0073] The directional flush port 122 includes a cap 124 that directsliquid supplied through an irrigation and insufflation lumen across thefront face of the distal tip 110 in the direction of the camera port 116and/or the illumination port 118. The cap 124 thereby serves to cleanthe camera port 116 and the illumination port 118 for a better view ofthe internal body cavity in which the imaging catheter is placed. Inaddition, the flushing liquid cleans an area of tissue surrounding thedistal end of the endoscope.

[0074]FIG. 7 shows further detail of one embodiment of a distal tip 110of the imaging endoscope. In this embodiment, the tip section 110includes a number of counter bored holes 126 that are positioned aroundthe circumference of the distal tip 110. The counter bored holes 126receive swaged or flanged ends of the control cables that orient thedistal tip. Tension on the control cables pull the distal tip 110 in thedirection of the tensioning force.

[0075]FIG. 8 is a lengthwise, cross-sectional view of an imagingendoscope 20 in accordance with one embodiment of the present invention.The distal tip 110 is adhesively secured, welded or otherwise bondedwithin a center lumen at the distal end of the articulation joint 30.Secured to the proximal end of the articulation joint 30 is a distal endof a shaft 128. As discussed above, the shaft 128 is preferably stifferor better able to transmit torque towards the distal end of theendoscope than at the proximal end of the endoscope.

[0076] The control cables 130 that move the distal tip of the endoscopeare preferably made of a non-stretching material such as stainless steelor a highly oriented polyethylene-theralate (PET) string. The controlcables may be routed within a center lumen of the shaft 128 or, as shownin FIG. 8, may be routed through lumens formed within the walls of theshaft. The control cables 130 extend through guides within the walls ofarticulation joint 30 and terminate either at the distal end of thearticulation joint 30 or in the distal tip section 110.

[0077] If the control cables are routed through the center lumen of theshaft 128, the cables are preferably carried in stainless steel orplastic spiral wrapped lumens to prevent binding and a transition guide140 such as that as shown in FIGS. 9A and 9B may be used to guide thecontrol cables into the proximal end of the articulation joint. Thetransition guide 140 has a proximal end 142 that is secured within alumen of the distal end of the shaft. A central body portion 144 of thetransition guide 140 has a diameter equal to the outer diameter of theimaging endoscope. In addition, the body portion 144 includes a numberof diagonal lumens 148 that extend from a center lumen of the proximalend 142 to an outer surface of a stepped distal end 146 of thetransition guide. The distal end 146 is secured within a proximal end ofthe articulation joint 30. Control cables in the diagonally extendinglumens 148 are therefore guided to the outer edge of the catheter wherethey extend through the guides or control cable lumens of thearticulation joint 30.

[0078]FIGS. 10A, 10B illustrate one embodiment of a shaft that comprisesthe imaging endoscope 20. The shaft 160 has a cover 162 that may includea wire or other braid 164 embedded therein. The braid 164, if present,allows the torque characteristics of the shaft to be adjusted. The cover162 may be formed by placing a sleeve over a mandrel. The braid 164 isplaced over the sleeve and the mandrel is dipped into or sprayed with acoating material. Preferably the sleeve and coating material are made ofpolyurethane or other biocompatible materials such as polyethylene,polypropylene or polyvinyl alcohol. In addition, the interior lumen(s)and exterior of the shaft can be coated with a extrudable, hydrophilic,lubricious coating such as the HYDROPASS™ hydrophilic coating availablefrom Boston Scientific, of Natick, Mass., and described in U.S. Pat.Nos. 5,702,754 and 6,048,620 which are herein incorporated by reference.

[0079] A plastic spiral wrap 166 such as spiral wire wrap available fromPanduit Inc. is inserted into a lumen of the cover 162. The spiral wrap166 prevents the shaft 160 from crushing as it is bent around apatient's anatomy.

[0080] In one embodiment of the shaft 160, the spiral wrap has athickness of 0.060 inches and a pitch of {fraction (3/16)} inch.However, it will be appreciated that other thicknesses of spiral wrapwith a different pitch could be used to provide the desired columnstrength and bend modulus as well as to prevent kinking.

[0081]FIG. 11 shows one method of altering the torque fidelity of thedistal and proximal portions of the shaft. The shaft 160 has a flexiblesection 170 that is proximal to the break out box and a stiffer section172 that is distal to the break out box. The portion of the scope thatis distal to the break out box has an increasing flexibility toward thedistal tip and conversely a higher torque fidelity and column strengthproximally. To increase the torque fidelity characteristics of thedistal section 172 of the shaft, a braid 164 in that section includestwo or more wires that are wound in opposite directions. In oneembodiment, the wire braid has a pitch of 14-16 pik. However, the numberof wires and their spacing can be adjusted as needed in order to tailorthe torque fidelity of the shaft.

[0082] The proximal end 170 of the shaft 160 has a single spiral of wire176 that is preferably wound in the same direction as the plastic spiralwrap 166 in the center lumen of the shaft 160. Again, the torquefidelity of the proximal end of the shaft 170 can be adjusted byadjusting the pitch and/or direction of the wire 176 and itsflexibility.

[0083] As will be appreciated, the single wire spiral 176 provides sometorque fidelity but does have the same torque fidelity as the dual wirebraid in the distal section of the shaft. The single wire spiral 176 maybe omitted from the proximal portion of the shaft if even less torquefidelity is desired.

[0084] In order to facilitate steering the distal tip of imagingendoscope, the endoscope includes an articulation joint that allows thedistal tip to be turned back on itself, i.e., over an arc of 180degrees, by the control cables. As shown FIG. 12A, 12B[,?] anarticulation joint 200 is formed from a cylinder of a plasticallydeformable material having a central lumen 202, and a number of controlwire lumens 204 located in the walls of the articulation joint. Ifdesired, the space between the control wire lumens in the cylinder wallmay be thinner such that the control wire lumens form bosses that extendinto the central lumen of the cylinder. The control cable lumens 204 arepreferably oriented at 120° apart if three control cables are used or90° apart if four control cables are used.

[0085] To facilitate bending of the articulation joint, the cylinderincludes a number of live hinges 220 formed along its length. As can beseen in FIG. 13, each live hinge 220 comprises a pair of opposingV-shaped cuts 230 on either side of the cylinder and are separated by aflexible web 232 that forms the bendable portion of the hinge. In theembodiment designed for four control cables, each live hinge is orientedat 90 degrees with respect to an adjacent hinge.

[0086] Upon retraction of a control cable, those live hinges having webs232 that are in line with the retracting control cable do not bend.Those live hinges having webs that are not in line with the controlcable will be closed, thereby bending the articulation joint in thedirection of the control cable under tension.

[0087] Another advantage of the articulation joint shown in FIG. 13 isthat the distal end of the scope can be retracted by pulling all thecontrol cables simultaneously. This allows the physician to maneuver thedistal tip in the body without having to move the remaining length ofthe endoscope. This may be useful when performing surgical proceduressuch as obtaining a biopsy or snaring polyps.

[0088] The articulation joint can be formed by extruding a cylinder withthe central and control cable lumens in place and cutting the cylindertube with a knife, laser, water jet, or other material removal mechanismto form the live hinges. Alternatively, the articulation joint can bemolded with the live hinge joints in place. As will be appreciated, theangles of the V-shaped cuts that form the hinges may be uniform or mayvary along the length of the articulation joint. Similarly, the distancebetween adjacent live hinges may be uniform or may vary in order totailor the bending and torque fidelity characteristics of thearticulation joint. In one embodiment of the invention, each live hingehas a closing angle of 30° so that six hinges are required to provide180° of movement. The distal end of the articulation joint 200 may becounter-bored to receive the distal tip section 110 of the endoscope, asdiscussed above. Similarly, the proximal end of the articulation joint200 is adapted to receive the distal end of the shaft of the endoscope.In the embodiment shown in FIG. 13, the control cable lumens 204 arealigned with the widest spacing of the live hinges and with the webportion of each hinge. However, it may be desirable to offset thecontrol cable lumens 204 with respect to the hinges in order to lessenpotential binding of the control cables in the hinge. As indicatedabove, the articulation joint should be made of a biocompatible materialthat will bend but will not collapse. Suitable materials includepolyurethane, polyethylene, polypropylene, or other biocompatiblepolymers.

[0089] To prevent wear by the control cables as they are pulled by theactuation mechanism in the motion control cabinet, it may be desirableto produce the articulation joint from a material having areas ofdifferent durometers. As shown in FIGS. 14 and 15, a cylinder formedfrom an extruded tube 240 has alternating bands of a high durometermaterial 242 and a lower durometer material 244 around itscircumference. The lumens 246 used to route the control cables areformed in the high durometer material to resist abrasion as the controlcables are tensioned and released. In addition, the high durometermaterial also reduces friction between the control cables and thesurrounding lumen. FIG. 15 illustrates an articulation joint where thecontrol cable lumens are offset with respect to the orientation of theweb portions 248 of the live hinges so that the control cables do notpass through the web portion of the hinge.

[0090]FIGS. 16A, 16B illustrate an alternative embodiment of anarticulation joint. In this embodiment, the joint comprises a series ofball and socket connectors that are linked together. As shown in FIG.16A, each connector includes a socket section 290 and a ball section292. The ball section 292 fits in a socket section 290 of an adjacentconnector. A lumen 294 extends axially through the ball section 292 toallow for passage of the wires that connect to the light source and theimage sensor and tubes that carry irrigation fluids and insufflationgases. The ball and socket sections are preferably molded of abiocompatible polymer.

[0091] Each socket section can be formed with a fully formed ballsection such as ball section 300 shown in FIG. 17A. Alternatively, apartial ball section such as ball section 304 can be formed on a socketsection 306 as shown in FIG. 17B. To provide room for the control cablesto move, the ball section can include slot 308 as shown in FIGS. 17A,17B that cuts through the middle and sides of the ball section.Alternatively, a number of smaller slots 310 can be positioned aroundthe circumference of the ball section as shown in FIGS. 17C and 17D. Theslots allow the control cables to be shortened under tension. A numberof holes 312 at the interface of the ball section and socket sectionallows passage of the control cables from the socket section into theball section as shown in FIG. 17D.

[0092] In another embodiment of an articulation joint, the joint is madeof a series of stacked discs that are positioned adjacent one anotherand move with respect to each other. As shown in FIG. 18A, a disc 350comprises an annular ring 352 having a pair of rearward facing rockersurfaces or cams 354 and a pair of forward facing rocker surfaces orcams 356. The cams 354 are positioned 180° apart on the rear surface ofthe annular ring 352, while the forward facing cams 356 are positioned180 degrees apart on the forward face of the annular ring 352. In theembodiment shown, the forward cams 356 are oriented at 90° with respectto the rear cams 354. Opposite each cam on the other side of the annularring is a flat land section so that the cams of an adjacent disc mayengage with and rock on the flat section. Holes 360 are drilled throughthe annular ring and through the cams for passage of the control cables.Upon tension of the control cables, the discs will rock on the surfaceof the cams 354, 356 thereby bending the articulation joint in thedesired direction.

[0093]FIG. 18B shows an articulation joint made up of a series ofstacked discs 350 a, 350 b, 350 c . . . engaged with one another to forman articulation joint. A number of control cables 370 a, 370 b, 370 c,370 d, pass through the discs and are used to pull the discs on the camsurfaces to move the joint in the desired direction.

[0094]FIGS. 19A and 19B show an alternative embodiment of thearticulation joint shown in FIGS. 18A and 18B. In this embodiment, anarticulation joint comprises a series of stacked discs 380, eachcomprising an annular ring having a pair of concave pockets 382 on itsrear surface and a pair of correspondingly shaped convex cams 384 on itsfront surface. The concave pockets 382 are oriented at 90° with respectto the convex cams 384 so that adjacent discs may be stacked such thatthe cams of a disc fit within the pockets of the adjacent disc. Thecorresponding shaped cams 384 and pockets 382 help prevent the discsfrom rotating with respect to one another. Holes or lumens 386 areformed through the annular ring 380 for passage of a number of controlcables 390 a, 390 b, 390 c, 390 d, as shown in FIG. 19B. The holes orlumens 386 may be positioned at the center of the cams and pockets.However, the holes for the control cables may be offset from theposition of the cams and pockets, if desired. Preferably discs 380 aremolded from a biocompatible polymer having a relatively slick surface,such as polyurethane, polypropylene, or polyethylene, that reducesfriction between adjacent cams and pockets.

[0095]FIGS. 20A and 20B show yet another alternative embodiment of anarticulation joint. In this embodiment, the articulation joint is formedof a stack of discs, each of which comprises an annular ring. Theannular ring has cams having an arcuate slot 392 molded therein thatallows a control cable to move more freely in the cam as the disc ismoved relative to an adjacent disc. As best shown in FIG. 20B, the slot392 tapers from a widest point 394 at the outer edge of the cam to anarrow point 396 where the slot forms a cylindrical hole 398 thatextends to the opposite edge of the annular ring 380. A control wire 390b is free to bend within the widened portion of the arcuate slot 392 asan adjacent disc is rotated.

[0096] Although the discs of the articulation joints shown in FIGS.18-20 are generally circular in shape, it will be appreciated that othershapes could be used. FIGS. 21A and 21B show an articulation jointformed from a number of sections having a generally square outer shape.As shown in FIG. 21A, a section 400 is a square band having a pair ofpins 402 that extend outwardly on opposite sides of the rear surface ofthe square section. On the opposite sides of the front surface are apair of opposing circular recesses 404 that are sized to receive theround pins 402 of an adjacent section. The embodiment shown, the controlcables are routed through holes or lumens in corner blocks 406 that arefound in each corner of the square section 400. FIG. 21B shows twoadjacent square sections 400 a, 400 b secured together. As can be seen,the section 400 b can rotate up or down on its pins with respect to theadjacent section 400 a. Although circular and square articulationsections have been shown, it will be appreciated that other segmentshapes such as triangular or pentagonal, etc., could also be used toform an articulation joint.

[0097] In some environments, a full 180° turning radius of the distaltip of the imaging endoscope may not be necessary. In thoseenvironments, the articulation joint may be replaced with a flexiblemember such as a braided stent. FIG. 22 shows an imaging endoscope 425having a braided stent 430 as the articulation joint. The braided stentextends between a distal tip 432 and a connector 434 that joins theproximal end of the stent 430 with the distal end of a flexible shaft436. A cover 438 extends over the flexible shaft 436 and the braidedstent 430. Control cables (not shown) extend through a lumen of flexibleshaft 436 and are used to pull the stent 430 such that the distal tip432 is oriented in the desired direction. In addition, pulling all thecontrol cables simultaneously allows the distal tip of the endoscope tobe retracted.

[0098]FIG. 23 shows one method of securing the distal ends of thecontrol cables to a braided stent 430. The control cables 440 a, 440 b,440 c, 440 d can be woven through the wires of the stent 430 andterminated by forming loops around the wires that comprise the stent.Alternatively, the ends of the cables 440 can be soldered or adhesivelysecured to the wires of the stent.

[0099] In some embodiments, the articulation joint is designed to exerta restoring force so that imaging endoscope will tend to straighten uponthe release of tension from the control cables. In other cases, it maybe desirable to maintain the position of the distal tip in a certaindirection. In that case, a construction as shown in FIG. 24 can be used.Here, the shaft of the imaging endoscope includes an inner sleeve 450that is overlaid with two or more plastic spiral wraps 452, 454, and456. Wrap 452 is wound in the clockwise direction while wrap 454 iswound in the counter-clockwise direction over the wrap 452 and the wrap456 is wound in the same direction as the first wrap 452. The wraps areformed of a relatively coarse plastic material such that friction iscreated between the alternatingly wound layers of the wrap. A suitablematerial for the plastic wrap includes a braided polyester orpolyurethane ribbon. Upon tension of the imaging endoscope by any of thecontrol cables, the plastic spiral wraps will move with respect to eachother and the friction between the overlapping wraps will tend tomaintain the orientation of the imaging endoscope in the desireddirection. The endoscope will remain in the desired direction until itis pulled in a different direction by the control cables. Covering thealternatingly wound spiral wraps 452, 454, and 456 is a braid 458. Thebraid is formed of one or more plastic or wire threads wound inalternate directions. An outer sleeve 460 covers the braid 458 tocomplete the shaft.

[0100]FIG. 25 shows another alternative embodiment of a shaftconstruction used in an imaging endoscope according to the presentinvention. The shaft includes a cover sheath 470 having bands of a highdurometer material 472 and a low durometer material 474 that alternatearound the circumference of the sheath 470. The high durometer materialand low durometer materials form longitudinal strips that extend alongthe length of the shaft. Within the sheath 470 is a plastic spiral wrap474 that prevents the shaft 470 from crushing as it is bent in apatient's anatomy. The high durometer materials add to the torquefidelity characteristics of the shaft. The width of the high durometermaterial strips compared to the low durometer material may be adjustedin accordance with the torque fidelity characteristics desired.

[0101] During examination with the imaging endoscope, the physician mayneed to twist the scope in order to guide it in the desired direction.Because the outer surface of the scope is preferably coated with alubricant and it is round, it can be difficult for the physician tomaintain an adequate purchase on the shaft in order to rotate it. Assuch, the imaging endoscope of the present invention may include agripper mechanism that aids the physician in grasping the shaft foreither rotating it or moving the shaft longitudinally. One embodiment ofa shaft gripping device is shown in FIG. 26. Here, a gripper 500comprises a unshaped member having a pair of legs 502, 504 that arealigned with the longitudinal axis of an imaging endoscope 20. At thedistal end of the legs 502, 504 are two 90° bends 506, 508. The gripper500 includes a hole 505 positioned at the curved bent portion of thegripper that joins the legs as well as holes in each of the 90° sections506, 508. The imaging endoscope passes through the holes such that thegripper 500 is slideable along the length of the shaft portion of theendoscope. The spring nature of the material used to fashion the grippercauses the legs 502, 504 to be biased away from the shaft of theendoscope. Only the friction of the opposing holes at the bent portions506, 508 prevent the gripper 500 from freely sliding along the length ofthe shaft. On the inner surface of the legs 502, 504 are a pair of touchpads 510, 512, having an inner surface that is shaped to match the outercircumference of the shaft portion of the endoscope. When the physiciansqueezes the legs 502, 504 radially inward, the touch pads 510, 512engage the shaft such that the physician can push or pull the endoscopeor rotate it. Upon release of the legs 502, 504, the touch pads 510, 512release from the surface of the shaft and the gripper 500 can be movedalong the length of the shaft to another location if desired.

[0102]FIG. 27 shows a gripper similar to that of FIG. 26 with like partsbeing identified with the same reference numbers. In this embodiment,the gripper includes two hemispherical discs 520, 522, positioned on theoutside surface of the legs 502, 504. The hemispherical surfaces 520,522 are designed to fit within the hand of the physician and increasethe radial distance from the gripper to the shaft such that it is easierto twist the shaft, if desired.

[0103]FIG. 28 shows yet another alternative embodiment of a shaftgripper. In this example, a gripper 550 comprises a u-shaped memberhaving a pair of legs 552, 554, that are oriented perpendicularly to thelongitudinal axis of the imaging endoscope 20. The legs 552, 554 includea recessed section 556, 558 that is shaped to receive the outer diameterof the shaft portion of the endoscope. A thumbscrew 560 is positioned atthe distal end of the legs such that the legs can be drawn together andcause the legs 554, 556 to securely engage the shaft of the endoscope.Upon release of the thumbscrew 560, the legs 554, 552 are biased awayfrom the shaft such that the gripper 550 can be moved. The shaft can betwisted by rotating the legs 552, 554, with respect to the longitudinalaxis of the shaft.

[0104]FIG. 29 shows an alternative embodiment of the gripper 550 shownin FIG. 28. In this example, the gripper 580 includes a u-shaped memberhaving a pair of legs 582, 584. At the distal end of each leg is arecess 586, 588 that is shaped to receive the outer diameter of theshaft. The shaft is placed in the recesses 586, 588, and a thumbscrew ispositioned between the ends of the legs 582, 584, and the u-shaped bendin the gripper 580. By tightening the thumbscrew 590, the legs arecompressed against the shaft of the imaging endoscope 20, therebyallowing the physician to rotate the endoscope by moving the gripper580.

[0105] In one embodiment of the invention the endoscope has a movablesleeve that operates to keep the distal end of the endoscope clean priorto use and covers the end of the scope that was in contact with apatient after the scope has been used.

[0106]FIGS. 30A and 30B illustrate one embodiment of an endoscope 594having a sponge 504 at its distal end. The sponge fits over theendoscope and has a peel off wrapper that may be removed and water orother liquid can be applied to the sponge. The water activates ahydrophilic coating so that the distal end of the endoscope has anincreased lubricity. In addition, the sponge functions as a gripper whencompressed allowing the physician to pull and/or twist the endoscope.

[0107] A collapsible sleeve 598 is positioned over the distal end of theendoscope and can be retracted to expose the lubricated distal tip ofthe probe. In one embodiment, the sleeve 598 is secured at its distalend to the sponge 594 and at its proximal end to the breakout box.Moving the sponge proximally retracts the sleeve so that the endoscopeis ready for use. After a procedure, the sponge 594 is moved distally toextend the sleeve over the distal end of the endoscope. With the sleeveextended, any contaminants on the probe are less likely to contact thepatient, the physician or staff performing the procedure.

[0108] In some instances, it may be desirable to limit the amount ofheat that is dissipated at the distal end of the imaging endoscope. Iflight emitting diodes are used, they generate heat in the process ofproducing light for illumination. Similarly, the image sensor generatessome heat during operation. In order to limit how hot the distal end ofthe endoscope may become and/or to provide for increased life for thesecomponents, it is necessary to dissipate the heat. One technique fordoing so is to fashion a heat sink at the distal tip of the imagingendoscope. As shown in FIG. 31, a distal tip 600 includes a cap 602 anda heat dissipating section 604 that is made of a heat dissipatingmaterial such as a biocompatible metal. The heat dissipating section 604includes a semicircular opening 606 having a relatively flat base 608that extends approximately along the diameter of the heat dissipatingsection 604. The flat base 608 forms a pad upon which electricalcomponents such as the LEDs and image sensor can be mounted with athermally conductive adhesive or other thermally conductive material.The heat generating devices will transfer heat generated duringoperation to the heat dissipating section 604. The distal cover 602covers the distal end of the heat dissipating section 604 in order toprevent the heat dissipating section 604 from touching the tissue in thebody as well as to protect the body as the imaging catheter is moved inthe patient. Prisms, lenses, or other light bending devices may beneeded to bend light entering the distal end of the endoscope to anyimaging electronics that are secured to the relatively flat base 608 ofthe heat dissipating section 604.

[0109]FIG. 32 shows a heat dissipating distal tip of an endoscopewherein the distal tip does not include a cover but is molded from asingle piece of heat dissipating material such as a biocompatible metal.The heat dissipating section 620 again includes a semicircular openingwith a relatively flat surface 622 that extends along the diameter ofthe section and on which heat generating electronic devices can bemounted. With a semicircular opening formed in the distal end of theheat dissipating distal tip 620, the illumination mechanism and imagesensor are mounted on the flat surface 622. The irrigation port isoriented to direct water over the hemispherical cutout in order to cleanthe illumination mechanism and image sensor or image sensor lenses.

[0110] In yet another embodiment of the invention, the imaging devicesat the distal end of the endoscope can be cooled by air or water passedthrough a lumen to the end of the endoscope and vented outside the body.For example, air under pressure may be vented through an orifice nearthe imaging electronics. The expansion of the air lowers its temperaturewhere it cools the imaging electronics. The warmed air is then forced tothe proximal end of the endoscope through an exhaust lumen.Alternatively, the endoscope may include a water delivery lumen thatdelivers water to a heat exchanger at the distal tip. Water warmed bythe electronic components in the distal tip is removed in a water returnlumen.

[0111]FIG. 33 shows an alternative embodiment of the heat dissipatingdistal tip shown in FIG. 31. In this example, the heat dissipatingdistal tip 640 has a number of scalloped channels 642 positioned aroundthe circumference of the distal tip. The scalloped channels 642 increasethe surface area of the heat dissipating distal tip, thereby furtherincreasing the ability of the tip to dissipate heat from theillumination and imaging electronic devices.

[0112] Although the present endoscopic imaging system has many uses, itis particularly suited for performing colonoscopic examinations. In oneembodiment, a 10-13 mm diameter prototype having a 0.060 inner spiralwrap with a pitch of {fraction (1/4)} inch and coated with a hydrophiliccoating was found to have a coefficient of friction of 0.15 compared to0.85 for conventional endoscopes. In addition, the endoscope of thepresent invention required 0.5 lbs. of force to push it through a 2-inchU-shaped bend where a conventional endoscope could not pass, throughsuch a tight bend. Therefore, the present invention allows colonoscopesto be made inexpensively and lightweight so that they are morecomfortable for the patient due to their lower coefficient of frictionand better trackability.

[0113] In addition to performing colonoscopies, the endoscopic imagingsystem of the present invention is also useful with a variety ofsurgical devices including: cannulas, guidewires, sphincterotomes, stoneretrieval balloons, retrieval baskets, dilatation balloons, stents,cytology brushes, ligation devices, electrohemostasis devices,sclerotherapy needles, snares and biopsy forceps.

[0114] Cannulas are used with the endoscopic imaging system to cannulatethe sphincter of Odi or papilla to gain access to the bile or pancreaticducts. Guidewires can be delivered down the working channel of theendoscope and used as a rail to deliver a surgical device to an area ofinterest. Sphincterotomes are used to open the papilla in order to placea stent or remove a stone from a patient. Stone retrieval balloons areused along with a guidewire to pull a stone out of a bile duct.Retrieval baskets are also used to remove stones from a bile duct.Dilatation balloons are used to open up strictures in thegastrointestinal, urinary or pulmonary tracts. Stents are used to openup strictures in the GI, urinary or pulmonary tracts. Stents can bemetal or plastic, self-expanding or mechanically expanded, and arenormally delivered from the distal end of a catheter. Cytology brushesare used at the end of guidewires to collect cell samples. Ligationdevices are used to ligate varices in the esophagus. Band ligatorsemploy elastic bands to cinch varices. Electrohemostasis devices useelectrical current to cauterize bleeding tissue in the GI tract.Sclerotherapy needles are used to inject coagulating or sealingsolutions into varices. Snares are used to remove polyps from the GItract, and biopsy forceps are used to collect tissue samples.

[0115] Examples of specific surgical procedures that can be treated withthe endoscopic imaging system of the present invention include thetreatment of gastroesophageal reflux disease (GERD) by the implantationof bulking agents, implants, fundoplication, tissue scarring, suturing,or replacement of valves or other techniques to aid in closure of thelower esophageal sphincter (LES).

[0116] Another example of a surgical procedure is the treatment ofmorbid obesity by deploying implants or performing reduction surgery,gastric bypass and plication or creating tissue folds to help patientslose weight.

[0117] Endoscopic mucosal resection (EMR) involves the removal ofsessile polyps or flat lesions by filling them with saline or the liketo lift them prior to resection. The endoscope of the present inventioncan be used to deliver needles, snares and biopsy forceps useful inperforming this procedure.

[0118] In addition, the endoscopic imaging system of the presentinvention can be used to perform full-thickness resection (FTRD) inwhich a portion of a GI tract wall is excised and the wounds healed withstaplers or fasteners. Finally, the endoscopic imaging system of thepresent invention can be used to deliver sclerosing agents to killtissues or drug delivery agents to treat maladies of internal bodytissues.

[0119] While the preferred embodiment of the invention has beenillustrated and described, it will be appreciated that various changescan be made therein without departing from the scope of the invention.For example, although some of the disclosed embodiments use the pullwires to compress the length of the endoscope, it will be appreciatedthat other mechanisms such as dedicated wires could be used.Alternatively, a spring can be used to bias the endoscope distally andwires used to compress the spring thereby shortening the length of theendoscope. Therefore, the scope of the invention is to be determinedfrom the following claims and equivalents thereof.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. An imaging endoscope,comprising: a shaft having a proximal end and a distal end; anillumination port at the distal end of the shaft for illuminatingtissue; an imaging port at the distal end of the shaft that includes animaging sensor to produce an image of the tissue; a plasticallydeformable articulation joint disposed at the distal end of the shaftcomprising a molded or extruded polymeric cylinder having a centrallumen and a number of control cable lumens disposed about thecircumference of the cylinder; a number of live hinges formed in thecylinder; and a number of control cables that are selectively activatedto bend the articulation joint in a desired direction.
 2. The imagingendoscope of claim 1, further comprising a working channel lumen in theshaft through which a medical device may be passed.
 3. The imagingendoscope of claim 1 wherein each live hinge comprises two or morediametrically opposed angled cutouts in the polymeric cylinder that arejoined by flexible webs.
 4. The imaging endoscope of claim 3, whereinthe control cables are aligned with the flexible webs of the livehinges.
 5. The imaging endoscope of claim 3, wherein the control cablesare offset from the flexible webs of the live hinges.
 6. The imagingendoscope of claim 3, wherein adjacent live hinges along the length ofthe articulation joint are rotated with respect to each other.
 7. Theimaging endoscope of claim 1, wherein the shaft is coated with alubricious material.
 8. The imaging endoscope of claim 1, wherein theshaft includes an insufflation/irrigation lumen.
 9. The imagingendoscope of claim 1, wherein at least a portion of the shaft includes aspiral wrap.
 10. The imaging endoscope of claim 9, wherein the spiralwrap is approximately 0.060 inches thick and has a pitch of about{fraction (3/16)} inches.
 11. The imaging endoscope of claim 1, whereinthe articulation joint comprises an extruded cylinder made of two ormore materials having different durometers.
 12. The imaging endoscope ofclaim 11, wherein the control cable lumens are within a material havinga higher durometer.
 13. The imaging endoscope of claim 1, wherein theshaft is covered by a sleeve that includes wound wrap.
 14. The imagingendoscope of claim 16, wherein the wrap has a number of threads and apitch selected to adjust the torque characteristics of the shaft. 15.The imaging endoscope of claim 16, wherein the threads of the wound wrapare made of wire.
 16. The imaging endoscope of claim 16, wherein thewound wrap has two or more threads that are braided.
 17. The imagingendoscope of claim 1, wherein the articulation joint is longitudinallyretractable by tensioning all the control cables.
 18. The imagingendoscope of claim 1, further comprising a sleeve that selectivelyexposes the distal end of the endoscope.
 19. An imaging endoscope,comprising: a shaft having a proximal end and a distal end; anillumination port at the distal end of the shaft for illuminatingtissue; an imaging port at the distal end of the shaft that includes animaging sensor to produce an image of the tissue; a plasticallydeformable articulation joint wherein the articulation joint includes anumber of stacked annular disks each having a number of holes throughwhich the control cables pass and camming surfaces that engage anadjacent annular disk in the articulation joint.
 20. The imagingendoscope of claim 19, wherein the camming surfaces of adjacent annulardisks are rotated with respect to each other.
 21. An imaging endoscopicsystem, comprising: a control cabinet including a number of actuatorsthat operate to control the orientation of an endoscope; an imagingboard for producing images received from an image sensor in anendoscope; one or more valves to control the delivery of an irrigationfluid and insufflation air/gas to one or more lumens in an endoscope; ahandheld controller including a number of controls that can be activatedby a physician to supply commands to the control cabinet; and a singleuse endoscope that is connectable to the control cabinet, the endoscopeincluding: a shaft with a proximal end and a distal end; an illuminationmechanism for illuminating tissue; an image sensor at the distal end ofthe endoscope for producing images of tissue; an articulation joint thatpermits the distal end of the endoscope to move; and a number of controlcables that are selectively tensioned by the actuators to orient thedistal tip of the endoscope.
 22. The imaging endoscope system of claim21, wherein the proximal end of the endoscope is connectable to thecontrol cabinet.
 23. The imaging endoscopic system of claim 21, whereinthe endoscope is connected to the control cabinet through the handheldcontroller.
 24. The imaging endoscopic system of claim 21, wherein thehandheld controller is connected to the control cabinet through a wiredlink.
 25. The imaging endoscopic system of claim 21 wherein the handheldcontroller is connected to the motion control cabinet through a wirelesslink.
 26. A system for obtaining images of a patient's internal bodycavity, comprising: a reusable control cabinet including: means forcontrolling the movement of a distal end of an endoscope; means forcontrolling the delivery of an irrigation fluid and/or an insufflationair/gas to lumen(s) of the endoscope; means for producing images oftissue received from signals produced by an image sensor at the distalend of an endoscope; an input mechanism for supplying signals to controlthe operation of the control cabinet; and a disposable endoscope that isconnectable to the control cabinet that obtains images of tissue in thebody cavity and is controllable by the control cabinet.
 27. The systemof claim 26, wherein the input mechanism comprises a handheld controllerconnected to the control cabinet with a wired link.
 28. The system ofclaim 26, wherein the input mechanism comprises a handheld controllerconnected to the control cabinet with a wireless link.
 29. An endoscope,comprising: a shaft having a proximal end, a distal end and a centrallumen extending therethrough; an illumination port at the distal end ofthe shaft; an imaging port including an image sensor at the distal endof the shaft; an articulation joint at or adjacent the distal end of theshaft comprising a molded or extruded polymeric cylinder having a numberof hinge mechanisms that can be opened and closed to bend the distal endof the shaft; and a number of control cables that are selectivelytensioned to close one or more of the hinge mechanisms of thearticulation joint.
 30. The endoscope of claim 29, wherein the shaft iscoated with a hydrophilic coating.
 31. The endoscope of claim 29,wherein the shaft includes a spiral wrap therein.
 32. The endoscope ofclaim 29, wherein the illumination port includes a number of lightemitting diodes.
 33. The endoscope of claim 29, wherein the illuminationport includes a number of optical fibers that direct illumination lightreceived from an external source.
 34. The endoscope of claim 29 whereinthe polymeric articulation joint is formed of two or more materials eachhaving a different durometer.
 35. The endoscope of claim 34, wherein thecontrol cables pass through lumens in the articulation joint that arewithin a material having a higher durometer.
 36. The endoscope of claim29, wherein the hinge mechanisms are equally spaced along the length ofthe articulation joint.
 37. The endoscope of claim 29, wherein the hingemechanisms are not equally spaced along the length of the articulationjoint.
 38. An imaging endoscope, comprising: a shaft having a proximalend, a distal end and a working channel lumen therein; a number ofcontrol cables that are connectable to a number of motion controllers tocontrol the orientation of the distal tip; an articulation jointcomprising a braided stent that is moved by the control cables to orientthe distal tip of the endoscope; one or more light emitting diodes atthe distal tip to produce illumination light; and an image sensor at thedistal end of the endoscope to produce images of tissue.
 39. The imagingendoscope of claims 40, further comprising: means for dissipating heatfrom the light emitting diodes and image sensor.
 40. The imagingendoscope of claim 38, further comprising a lumen into which a liquid orgas is delivered and an orifice in the lumen adjacent the light emittingdiode and image sensor to direct the air or gas over the light emittingdiodes and image sensor to dissipate heat.
 41. An endoscope for viewinginternal body cavities of a patient, comprising: a shaft having acentral lumen and a braid embedded within a wall of the shaft; aplastically deformable articulation joint at or adjacent a distal end ofthe endoscope, the articulation joint including a number of live hingesand lumens through which control cables are passed; a number of controlcables within the lumens of the articulation joint; wherein the distalend of the endoscope may be turned in a desired direction by selectivelytightening control cables and the distal tip of the endoscope can beretracted by tightening all the control cables simultaneously.
 42. Theendoscope of claim 45, wherein the control cables are made of metal. 43.The endoscope of claim 45, wherein the control cables are made of PET.44. The endoscope of claim 41, wherein the control cables are routedwithin spiral wrapped lumens within the sleeve.
 45. An endoscope forviewing internal body cavities of a patient, comprising: a shaft havinga lumen therein; an articulation joint at or near the distal end of theshaft for selectively orienting the distal end of the shaft; an imagingsystem positioned at or adjacent the distal end of the shaft including alight source and an image sensor for capturing images of the patient'sbody cavity; and a retractable sleeve that selectively uncovers thedistal end of the shaft for use with a patient and recovers the distalend of the shaft after a patient examination procedure.
 46. Theendoscope of claim 45, wherein the retractable sleeve is connected to agripper on the shaft that is used to rotate the shaft.
 47. The endoscopeof claim 46, wherein the shaft is coated with a hydrophilic coating andthe gripper includes a sponge that can be wetted to activate thehydrophilic coating.